Electric Strain Gauges Method in the Effectiveness Assessment for the C-Frame Crank Press Elastic Compensators

The electric strain gauges method application to the elastic compensators effectiveness assessment for the "press-die" system of C-frame (gap-frame) presses is shown. The electric Wheatstone bridge was adapted, where the one arm is used on the equal mechanical stress calibration beam, and the other arm on the section of the press frame, which experiences maximum tensile stresses. The bridge arms' active and ballast purpose changed during calibration and research. After receiving the calibration characteristic between the current on the ammeter and mechanical stresses, the stress level in the press frame was estimated using various elastic compensators aimed at reducing them. It is shown that the use of elastic compensators based on polyurethane elastomers can reduce parasitic loads in the press frame by 15-42% compared to tensile stresses arising in the frame without a compensator. It has been established that the highest compensators efficiency is observed in the range of their upsetting up to 20-30%.